WSDL Gets Close Look

W3C to examine Web services specifications, including WSDL.

NEW YORK--Major software vendors have touted WSDL as a key specification for driving the interoperable world of Web services.
But some developers say its patrons are using Web Services Description Language and other standards to force enterprises into choosing one vendors Web services initiative over anothers, effectively removing the openness and interoperability that are cornerstones of the technology. WSDL, largely written by IBM and Microsoft Corp., details a machine-readable way to describe Web services. This description includes everything needed to make a Web service call.
But where some developers say WSDL, which became a de facto standard after IBM and Microsoft issued the code, is unnecessary and counterproductive, others say the specification needs to be fixed. Still others say its crucial to Web services.

To clarify the matter, the World Wide Web Consortium last month created a working group to look at Web services standards, including WSDL. The group, chaired by Microsoft, has its first conference call this week.

Dave Winer, a developer and CEO of UserLand Software Inc., in Millbrae, Calif., said WSDL is an unnecessary piece of standards infrastructure for Web services and exists largely as a way for big companies such as Microsoft, IBM and Sun Microsystems Inc. to set up entry barriers to smaller competitors. Winer said there is no need for WSDL "unless you are trying to lock developers into your development environment, as Microsoft and Sun and IBM surely are trying to do." Instead, developers and vendors should use normal programming techniques or Simple Object Access Protocol schemas, which he and others said are more open and less complex than WSDL.
Barriers to competition occur when smaller enterprises must decide whether to bet their Web services strategy on a company such as Microsoft, IBM, Oracle Corp. or Sun, all of which offer "some level of proprietary code that locks you into their solution," said Britt Johnston, chief technology officer at NuSphere Corp., a Bedford, Mass., open-source technology vendor.
"The level of lock-in thats possible if you take some of these Web services solutions from top to bottom is unprecedented," he said last week while at LinuxWorld here. WSDL "is one of the places where Microsoft is really trying to instant the standard ... and using that as a way to increase the complexity of the .Net service."
Bill Schultz, a spokesman with Microsoft, in Redmond, Wash., said the company would not comment on the concept of lock-in and WSDL.
Rich Salz, CTO of Zolera Systems Inc., in Waltham, Mass., and a member of the WSDL working group, said the specification is necessary but flawed.
"The people who say its not necessary are those who are focusing on simple things," Salz said. "But if I want to do complicated document exchange, I need some sort of automation," which WSDL provides.

Darryl K. Taft covers the development tools and developer-related issues beat from his office in Baltimore. He has more than 10 years of experience in the business and is always looking for the next scoop. Taft is a member of the Association for Computing Machinery (ACM) and was named 'one of the most active middleware reporters in the world' by The Middleware Co. He also has his own card in the 'Who's Who in Enterprise Java' deck.